Title:
GROUND FAULT DETECTING METHOD AND APPARATUS THEREFOR
Document Type and Number:
Japanese Patent JP3718141
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a compact ground fault detecting apparatus by detecting zero-phase current and overcurrent flowing through a distribution line using a current transformer.
SOLUTION: In the invention, when a ground voltage is detected through a limiting resistor 17A and a ground overvoltage relay 12 in the tertiary open delta circuit 10C of a transformer 10 for grounded instruments, the switching circuit 18 is closed to form a low impedance circuit 17 so that the ground fault current i1 flowing in the distribution line is detected by a transformer 5, thereby omitting a zero-phase transformer.
Inventors:
Naoki Kawamura
Minoru Kanai
Yasunobu Fujita
Yuzo Shibata
Minoru Kanai
Yasunobu Fujita
Yuzo Shibata
Application Number:
JP2001153719A
Publication Date:
November 16, 2005
Filing Date:
May 23, 2001
Export Citation:
Assignee:
株式会社日立製作所
International Classes:
H02H3/34; G01R19/00; G01R31/02; H02H3/38; (IPC1-7): H02H3/34; H02H3/38
Domestic Patent References:
| JP3251028A | ||||
| JP6086451A | ||||
| JP55083829U | ||||
| JP3011921A |
Attorney, Agent or Firm:
Katsuo Ogawa
Kyosuke Tanaka
Takashi Sasaki
Kyosuke Tanaka
Takashi Sasaki